KR20040097334A - Multi-directional scanning of movable member and ion beam monitoring arrangement therefor - Google Patents

Abstract

A semiconductor processing apparatus is disclosed that moves a scanning arm 60 of a substrate or wafer holder 180 in at least two generally perpendicular directions (so-called X-Y scanning). Scanning in the first direction penetrates longitudinally through the hole 55 in the vacuum chamber wall. Arm 60 is reciprocated by one or more linear motors 90A, 90B. Arm 60 is supported against slide 100 using gimbaled air bearings to provide cantilever support for slide 100 to the arm. The compliant feedthroughs 130 into the vacuum chamber for the arm 60 function as vacuum seals and guides but need not provide bearing support by themselves. Faraday 450 is attached to arm 60 adjacent the substrate holder such that beam profiling can be performed before and during implantation. Faraday 450 may be mounted at the back of the substrate holder or at 90 ° such that beam profiling may be performed prior to implantation.

Description

MULTI-DIRECTIONAL SCANNING OF MOVABLE MEMBER AND ION BEAM MONITORING ARRANGEMENT THEREFOR}

In a typical ion implanter, a beam of dopant ions of relatively small cross-sectional area is scanned against a silicon wafer. This can be accomplished in essentially one of three ways: by scanning the beam in two directions for the stationary wafer, by scanning the wafer in two directions for the stationary beam, or by the beam being scanned in one direction. A hybrid technique in which a wafer is mechanically scanned in a second direction, typically in the vertical direction.

Each method has advantages and disadvantages. For smaller silicon wafers, a conventional approach has been to mount a batch of wafers at the spoke end of the rotating wheel. The wheel is then scanned back and forth to cause the fixed ion beam to impinge on each wafer.

A batch process is currently not desirable for larger (300 mm) wafers. One reason for this is that the problem arises that the individual cost for each wafer poses significant financial risk. Electrostatically or magnetically scanning the ion beam in the vertical direction with respect to the stationary wafer tends to result in worse quality beams, and current single wafer scanning techniques employ hybrid mechanical / electrostatic scanning as outlined above. Tend to. Appropriate devices for accomplishing this are described in our co-acquired US Pat. No. 5,898,179, the contents of which are hereby incorporated by reference in their entirety. Here, the ion beam is magnetically scanned in a first direction perpendicular to the beam line axis of the ion implanter, while the wafer is mechanically moved in a second axis that is generally perpendicular.

Nevertheless, there are advantages to maintaining the stationary beam direction (in terms of beam profile, beam stability and minimization of beam line length). This in turn requires dual direction scanning of the wafer. It is an object of the present invention to provide a device which achieves this.

It is generally desirable to determine the beam profile, ie the ion density expressed as a function of the distance across the beam in a given direction, especially when the beam is in a fixed direction relative to the injection chamber. This is because the wafer passing speed across the beam is slower than hybrid scanning. Thus, for proper wafer throughput, it is necessary to minimize the raster pitch. For example, it is helpful to determine the beam profile (ie beam current intensity for the cross-sectional area of the beam) before and during the injection. Determining the beam profile prior to implantation allows the scanning of the wafer to be controlled during implantation to ensure certainness for the wafer, rather than a low, high ion density 'stripe'.

Many approaches to determining the beam profile are known to those skilled in the art. For example, in our co-acquired PCT patent application WO-A-00 / 05744, the signal output from the beam stop (located downstream of the batch processing wafer holder) is shown in the beam width, height and Adopted to obtain information about continuity. The signal processing depends on the spacing between the wafers on the rotary wafer holder and therefore is not appropriate for a single wafer.

Another beam profile determination technique includes a traveling faraday as described in US Pat. No. 5,898,179, referenced above, and a pair of fares held in a fixed position and spaced along the beamline.

Accordingly, the present invention seeks to provide an improved ion beam profile determination device, particularly for use during pre-implantation setup.

The present invention relates to a method and apparatus for scanning a movable member, such as a semiconductor wafer holder, in a number of different directions with respect to an ion beam. The invention also relates to an ion beam monitoring device for use in the device.

1A is a side view of an ion implanter including a process chamber equipped with a substrate scanning device including a scanning arm support structure in accordance with the present invention.

FIG. 2B is a partial cross sectional view along line AA of FIG. 1A.

FIG. 2 is a more detailed perspective view of the substrate scanning apparatus of FIGS. 1A and 1B.

3 is a side cross-sectional view of the substrate scanning apparatus of FIG. 2.

4 is an enlarged view of area A of FIG. 3.

5 is a perspective view of a substrate support attached to the substrate scanning apparatus of FIGS. 1 to 4 and including Faraday.

FIG. 6 shows a portion of Faraday of FIG. 5 while Faraday crosses the ion beam.

7 is a side view of the substrate support and Faraday of FIG.

8 is a front view of an alternative arrangement of substrate support and Faraday.

9 is a partial cross-sectional view of the faraday of FIGS. 5 and 8.

Accordingly, one aspect of the present invention is to provide a semiconductor processing apparatus that allows an elongate member, such as an arm of a substrate or wafer holder, to be movable in at least two typically vertical directions (so-called XY scanning). . Scanning in the first direction passes longitudinally through the hole in the vacuum chamber wall. For example, the elongate member is reciprocated by an elongate member driver, such as a pair of linear motors. Each of the elongate member and driver is preferably mounted on a carrier driven in a second direction, generally perpendicular to the first direction.

The carrier preferably comprises a slide to enable longitudinal reciprocation of the elongate member. The elongate member is preferably supported against a slide that is cantilevered from a pair of carriers. The term "cantilevered" will be understood to mean not only horizontal support but also support in a vertical or other direction.

In a particularly preferred feature of the invention, the elongate member is spaced by one or more gimbaled bearings positioned towards the first end of the elongate member. These bearings provide cantilevered support for the elongate member as it moves back and forth along the slide. Using this technique, a feedthrough may be provided for the elongate member to enter the vacuum chamber, which functions as a vacuum seal but does not need to provide bearing support on its own. The feedthrough preferably has compliance and another aspect of the invention provides a plurality of elastic gaskets and the like to function as a vacuum seal and enable compliance of the feedthrough to the carrier or vacuum chamber wall. do.

The feedthrough is preferably a rotary feedthrough. This allows the elongate member to rotate about an axis parallel to the longitudinal direction.

In another aspect of the invention, Faraday is attached to the elongate member adjacent the substrate support. This allows the beam (ion beam having a fixed direction relative to the vacuum chamber) to be performed in the substrate plane to be implanted. Pre-implant beam profiling can be performed so that the beam line can be "tuned", as well as the beam being profiled during a portion of the implant cycle due to the presence of Faraday adjacent the front portion of the substrate support. .

The elongate member is rotatable about its own axis, so that the Faraday can be mounted, alternatively or additionally, adjacent the back of the substrate support. Beam profiling may be performed with the substrate support inverted (rotated 180 °). By coating the back side of the substrate support with a semiconductor material (eg, silicon), beam profiling can be performed without the need for a dummy wafer to be secured to the “front portion” of the substrate support. Alternatively, or in addition, the Faraday may be mounted such that the Faraday enters 90 ° into the planes of the front and back of the substrate support.

Accordingly, the present invention in a first aspect provides a semiconductor processing apparatus, comprising: a vacuum chamber having a chamber wall having holes; An elongate member extending through said hole in said chamber wall and movable through said chamber wall in a longitudinal direction; An elongate member driver disposed so that the elongate member reciprocates in the longitudinal direction; A carrier outside the vacuum chamber for supporting the elongate member and the driver; And a carrier driver arranged to reciprocate in a direction generally perpendicular to the reciprocating direction of the movable elongate member.

According to a second aspect of the invention, a semiconductor processing apparatus is provided, the apparatus comprising: a vacuum chamber having a chamber wall; An elongate member extending horizontally through the chamber wall and movable in the longitudinal direction through the chamber wall; An elongate member driver arranged to drive the elongate member in the longitudinal direction; A carrier for supporting the elongate member and the driver that is external to the vacuum chamber and provides cantilever support for an outer end of the elongate member; And a feedthrough into the vacuum chamber for receiving the elongate member and including a vacuum seal for sealing the elongate member.

In another aspect there is provided a method of mounting an elongate member for reciprocating movement into and out of a vacuum chamber of a semiconductor processing apparatus, the method comprising: (a) the elongate member-the elongate member Supporting against a carrier external to the vacuum chamber, supported by at least one load bearing device positioned towards the first end of the elongate member; And (b) mounting the elongate member to penetrate a vacuum seal between the interior and exterior of the vacuum chamber; The rod represented by the elongate member is substantially supported by the rod bearing devices or each thereof so that the vacuum seal functions as a non-load bearing guide for the elongate member during reciprocating movement. .

In another aspect, a rotary and linear vacuum seal for a feedthrough of an elongate member extending into a vacuum chamber of a semiconductor processing apparatus is provided, the vacuum chamber having a chamber wall member, the vacuum seal being An outer mounting portion fixed to the wall member and having a longitudinal axis extending in a direction passing through the chamber wall member; It is radially mounted inside the outer mounting portion and is movable relative to the outer mounting portion, the elongate member is sized to be accommodated therethrough and extends in the direction extending through the chamber wall as well. An internal bearing having an axis; And a plurality of compliant gaskets disposed between the inner bearing and the outer mount and spaced axially along the longitudinal axis of the inner bearing and the outer mount.

Another aspect of the invention provides a semiconductor processing equipment, the apparatus comprising: a vacuum chamber having a chamber wall having holes; Opposing an elongate member extending through the aperture of the chamber wall and a front portion adapted to receive a substrate attached to a first end of the elongate member and located within the vacuum chamber and adapted to be processed; A substrate scanning device including a substrate support including a rear surface; Scanning device driving means for moving said substrate scanning device in a first direction generally penetrating said chamber wall in a longitudinal direction and in a second direction generally perpendicular to said first direction; And a Faraday mounted in a fixed relationship therewith adjacent the substrate support.

In another aspect, there is provided a method of profiling an ion beam in a semiconductor processing apparatus, the apparatus comprising a vacuum chamber having a chamber wall with holes, and an elongate arm extending through the hole in the chamber wall. And a beam scanning device attached to the first end of the elongate arm and including a substrate support positioned within the vacuum chamber, the substrate support adapted to receive a substrate to be processed, and the front portion A back portion opposing the; The ion beam profiling method comprises: mounting Faraday in a fixed association therewith adjacent to the substrate support; In either direction, the first direction generally penetrating the chamber wall in a longitudinal direction and the second direction generally perpendicular to the first direction, the ion beam is generally aligned with the first or second direction in the Faraday, respectively. Moving the beam scanning apparatus until it is completed; Scanning the beam scanning device in a direction of the other of the first and second directions such that the ion beam passes across the faraday; Obtaining a Faraday output signal while the beam scanning device is scanning across the Faraday; And obtaining a profile of an ion beam in the other one of the first and second directions from the Faraday output signal.

The invention also extends to an ion implanter comprising a semiconductor processing apparatus and / or a vacuum feedthrough as outlined above. It is also to be understood that the various aspects of the invention are not mutually exclusive and that in practice the combination of the various aspects of the invention is advantageous.

A side view of the ion implanter is shown in FIG. 1A. A partial cross sectional view at line AA of FIG. 1A is shown in FIG. 1B. As best shown in FIG. 1A, the ion implanter includes an ion source 10 arranged to generate an ion beam 15. Ion beam 15 is guided into mass analyzer 20 where ions of a desired mass / charge ratio are electromagnetically selected. Such techniques are apparent to those skilled in the art and will no longer be described in detail. For convenience, in FIG. 1A the mass spectrometer 20 is shown to bend the ion beams from the source 10 on a paper plane that is perpendicular to the other portions of the injector shown. In practice, the analyzer 20 is typically arranged to bend this ion beam in a horizontal plane.

The ion beam 15 exiting the mass spectrometer 20 is electrostatic accelerated or electrostatically decelerated, depending on the type of implanted ions and the desired implant depth.

Downstream of the mass spectrometer is a process or vacuum chamber 40 that includes a wafer 180 to be implanted, as can be seen in FIG. 1B. In this embodiment, the wafer is, for example, a single wafer of 200 mm or 300 mm diameter. Typically, the ion beam exiting the mass spectrometer 20 has a beam width and height that is substantially smaller than the diameter of the wafer to be implanted. The scanning device (described in detail below) of FIGS. 1A and 1B contemplates scanning the wafer in multiple directions such that the ion beam is maintained along a fixed axis to the vacuum chamber 40 upon injection. Specifically, the wafer is mounted on a substrate support, which consists of a plate on which the wafer is mounted within the vacuum chamber 40 and an elongate arm 60 connected to the plate.

The elongate arm 60 extends through the wall of the process chamber in a direction generally perpendicular to the ion beam direction. The arm passes through a slot 55 (FIG. 1B) of a rotor plate 50 mounted adjacent to the sidewall of the process chamber 40. The end of the scanning arm 60 is mounted through a sledge. The scanning arm 60 is substantially fixed in the y-direction with respect to the sledge 70 as shown in FIGS. 1A and 1B, and the scanning plane can be rotated in the direction R (FIG. 1A) as described further below. have. The sledge 70 is reciprocally movable with respect to the rotating plate 50 in the direction Y shown in FIGS. 1A and 1B. This allows for reciprocating movement of the substrate within the process chamber 40.

The scanning arm 60 is mounted to the scanning arm support structure 30 for mechanical scanning in the vertical X-direction (ie, in the direction of entering and exiting the paper plane in FIG. 1A, from left to right in FIG. 1B). . As shown in FIG. 1A, the scanning arm support structure 30 includes a pair of linear motors 90A, 90B spaced up and down from the longitudinal axis of the scanning arm 60. Preferably, the force is mounted about the longitudinal axis such that the force coincides with the center of mass of the scanning arm support structure 30. However, this is not essential and it will of course be understood that a single motor may be employed instead to reduce weight and / or cost.

The support structure 30 also includes a slide 100 mounted in a fixed relationship with the sledge 70. The movement of the linear motors along the tracks arranged left to right in FIG. 1B (not shown in FIG. 1A or 1B) causes the scanning arm 60 to reciprocate from left to right as shown in FIG. 1B as well. The scanning arm 60 reciprocates relative to the slide 100 on a series of bearings.

In this arrangement, the substrate is movable in two perpendicular directions (X and Y) with respect to the axis of the ion beam 15 so that the entire substrate is moved across the fixed ion beam direction.

The sledge 70 in FIG. 1A is shown in a vertical position such that the surface of the wafer is perpendicular to the incident ion beam axis. However, it may be desirable to implant the ions of the ion beam into the substrate at an angle. For this reason, the rotating plate 50 is rotatable about a wall of the vacuum chamber 40 fixed about an axis defined as its center. In other words, the rotating plate 50 may rotate in the direction of the arrow shown in FIG. 1A.

Movement of the sledge 70 relative to the rotor plate 50 is facilitated by an air bearing between the rotor plate 50 surface and the sledge 70 surface. The movement of the rotor plate 50 relative to the process chamber 40 is likewise a stator (not shown) mounted on a surface of the rotor plate 50 and a flange extending radially from the wall of the process chamber 40 adjacent to the aperture. It is facilitated by the air bearing between the surfaces of the. Radial movement of the turntable is limited by a series of guide wheels 80 disposed around the circumference of the turntable 50. Unnecessary axial movement of the tumbler is prevented by using the pressure difference between the two tumbler faces: the outer face is under atmospheric pressure while the inner face is under vacuum so that a considerable force is exerted toward the paper plane of FIG. Is in a state. The sledge 70 is likewise secured relative to the swivel plate 50 by the pressure difference between the sledge outer surface and the sledge inner surface on which the sledge covers the hole in the wall of the process chamber.

Details of the mounting method (including fluid bearings) for the stator on the rotor plate 50 and the process chamber wall are all described in detail in UA-A-5,898,179, the contents of which are incorporated herein in their entirety. The mounting method of the sledge 70 for reciprocating movement in the Y-direction is likewise described in the above patent. Details of air bearings, which are particularly suitable between the rotor and stator and between the sledge and the rotor, include porous graphite material and differentially-pumped vacuum seals, are described in our pending application USSN. No. 09 / 527,029 (corresponding to published UK patent application GB-A-2,360,332), the contents of which are incorporated herein in their entirety. An annular piston member may be used to support the rotor plate 50 against the stator to prevent "bowing" or "dishing" of the rotor plate 50, which is commonly assigned US Patent US-B1. 6,271,530. The contents of this patent are also incorporated herein.

The scanning arm support structure will be described in more detail with reference to FIGS. 2 and 3. 2 is a more detailed projection of the substrate scanning apparatus of FIGS. 1A and 1B at a preferred angle and includes a scanning arm support structure 30. 3 is a side cross-sectional view of the shape shown in FIG. 2.

As can be seen in FIGS. 2 and 3, the scanning arm support structure 30 is cantilevered from the sledge 70. An air bearing 110 for the sledge 70 is shown in FIG. 2. Further details regarding this differentially-pumped air bearing 110 are described in the above-cited US-A-5,898,179, and a more detailed description of this part of the substrate scanning apparatus will not be provided herein.

The scanning arm 60 reciprocates in the horizontal plane and there is a bending moment for it since the scanning arm has a weight that cannot be ignored. More specifically, when the scanning arm 60 is initially in the retracted position as shown in FIG. 3, the weight of the scanning arm is determined by the scanning arm support structure 30, the sledge 70 and the rotating plate ( 50). However, if the scanning arm is in its normally extended position (ie, the scanning arm 60 has been moved to the right as shown in FIG. 3), the center of gravity of the scanning arm 60 is directed to the chamber wall. Is moved horizontally with respect to the Thus, there is a load variation with respect to the various extension states of the scanning arm. In addition, the scanning arm 60 is preferably rotatable about its longitudinal axis S-S (FIG. 3), which additionally necessitates a feedthrough from the atmosphere to the vacuum. It is also important that the surface of the scanning arm 60 is not in contact with the vacuum feedthrough, since the contact causes wear. In addition, it is difficult to manufacture the cylindrical feedthrough so as to have appropriate durability, in particular in terms of load variation.

To solve these problems, a cantilevered support for the scanning arm 60 is adopted instead. Using a set of cantilever bearings 120A, 120B, 120C and 120D, the scanning arm 60 is supported relative to the slide 100 at the end 60A away from the vacuum chamber 40. In this arrangement, the scanning arm 60 may pass through the compliant vacuum feedthrough 130 into the vacuum chamber 40. The feedthrough 130 is mounted in the hole 140 of the sledge 70. By mounting the distal end 60A of the scanning arm 60 onto the cantilever bearings 120, the feedthrough 130 does not need to provide a bearing support, but instead a vacuum-tight seal for the scanning arm 60. It functions only as a vacuum-tight seal. The compliance of the feedthrough 130 accommodates any small misalignment between the feedthrough and the cantilever bearings 120.

The feedthrough also enables a rotational movement about its own axis S-S of the scanning arm 60. This is accomplished by providing a motor for driving the scanning arm 60 at the distal end 60A. The purpose of providing a rotational motion of the scanning arm 60 will be described below with respect to FIGS. 5 to 7.

Additional details about the resilient vacuum feedthrough 130 will be provided below with reference to FIG. 4.

The scanning arm 60 is provided with a pair of linear motors 90A and 90B for driving forward and backward along the axis S-S. As can be seen in Figure 3, these linear motors are spaced at equal intervals above and below axis S-S, respectively. The linear motors are connected to the end 60A of the scanning arm 60 with a connection bracket 150. With this arrangement, the force exerted on the scanning arm by the linear motors is exerted substantially along the axis S-S, minimizing the risk of any bending moments that may occur for a single, offset linear motor.

The scanning arm 60 is surrounded by an elastomeric gaiter 160 in the atmospheric portion of the sledge 70. Gator 160 is provided with dry air and prevents airborne contaminants from entering the vacuum chamber 40 as the arm moves from left to right.

The scanning arm support structure has considerable weight, which means that control over the linear motor that drives the scanning arm support structure 30 in the y-direction relative to the sledge 70 may be difficult. In order to solve this problem, vacuum piston counterbalances 170 are provided, in which only one of them is shown. Each of the vacuum piston balances 170 has an axis generally parallel to the y-direction. Such a device is described in more detail in commonly assigned US patent application Ser. No. 09 / 293,956 and in some continuing applications of September 20, 2001, the contents of each application being incorporated herein. Published European Patent Application EP-A-1,047,102 corresponds to USSN 09 / 293,956.

Since the end 60A of the scanning arm 60 is under atmospheric pressure, while the axially opposite end of the scanning arm 60, to which the substrate support 180 is attached, remains in the vacuum chamber 40, the scanning arm 60 Along the axis SS (from left to right in FIG. 3) there will be a significant force. Thus, as best seen in FIG. 2, the scanning arm vacuum piston balances 190 are again mounted between the stationary and moving portions of the scanning arm support structure 30.

The cantilever bearings 120 will now be described in more detail in conjunction with the mounting method for the slide 100. Each cantilever bearing 120 includes a bearing head and an elastic bearing support 210. Elastic bearing supports 210 of the lower cantilever bearings 120B and 120D are mounted on the lower linear motor 90B. The upper elastic bearing supports 210 are mounted on the scanning arm 60 at the distal end 60A; However, the scanning arm 60 is forced to move with the upper linear motor 90A by the connecting bracket 150.

The bearing heads 200 of the lower cantilever bearings 120B, 120D are mounted to bear the lower surface 220 of the slide 100. The bearing heads 200 of the upper cantilever bearings 120A, 120C are mounted to bear the upper surface 230 of the slide 100.

The bearing heads 200 preferably comprise bearing pads formed of graphite or other porous material. As described in USSN 09 / 527,029 referenced above, the use of graphite results in a constant flow rate of air through the bearing surface area. This in turn allows lower "ride heights" to be achieved. The slide 100 is formed of or coated with a ceramic material such as alumina so that the frictional force between the two bearing surfaces is minimal even when the bearing head 200 contacts the slide 100 surface during movement. .

When the cantilever bearings 120 operate, the bearing heads 200 extend toward the surfaces until they reach the surfaces 220, 230 of the slide 100. This process is accomplished by elastic bearing supports. It will be understood that the particular arrangement of cantilever bearings 120 means that the bearing heads are gimbaled and thus automatically level with respect to the surfaces 220, 230 of the slide 100.

When the bearing heads are tightened firmly to the bearing surfaces 220, 230 of the slide 100, a supply of air or other fluid flows through the graphite of each bearing head 200. Each bearing head 200 has a small plenum (not shown) adjacent the graphite bearing surface, and compressed air is supplied to the plenum via a tube (not shown). The tube exits the plenum and passes through each resilient bearing support 210 to supply compressed air along the cable and pipe duct 240 and then exits the scanning arm support structure 230.

As the air flow rate from the air supply increases, the bearing heads 200 are lifted from the surfaces 220, 230 of the slide 100 so that the scanning arm 60 can be moved relative to the slide. The slide is fixed at least in the x-direction relative to the arm when the scanning arm 60 moves; Preferably the slide is mounted directly to the sledge 70.

Cable and pipe line 240 (which carries pipes that supply compressed air to several air bearings) is compliant. This allows the first end of the tube 240 to be attached to the relative fixation of the substrate scanning device and the second end to the relative movement. For example, the end 240A (shown best in FIG. 2) of the cable and pipe conduit 240 does not move relative to the scanning arm support structure 30, while the other end 240B is the scanning arm. If 60 moves back and forth in the x-direction, it moves with it.

The support structure described above enables high speed, mechanical X-Y scanning. By way of example only, the scanning arm 60 may have a stroke of about 470 mm. The scan frequency in the longitudinal direction X may be 1.5 kHz. The time required at each end of the 78 ms longitudinal scanning movement results in acceleration and deceleration on the order of 4G. The linear velocity of the main part of each stroke is about 2 m / sec. Each Y step (at the end of each longitudinal stroke) can be any position between 0 and 30 cm and the acceleration can be about 2G.

A preferred embodiment of a compliant vacuum feedthrough 130 will now be described with reference to FIG. 4, which is an enlarged view of area A of FIG. 3. The feedthrough 130 is generally cylindrical, in particular having a cylindrical bore having a diameter sufficient to receive the cylindrical scanning arm 60. The vacuum feedthrough includes an outer sheath, generally designated 260, and an inner sheath, generally designated 270, which is inside the outer sheath and has an axis like that. The outer lid 260 is secured to the sledge 70 adjacent to the aperture 140 of the sledge 70 (only a portion of which is shown in FIG. 4). Alternatively, the inner sheath 270 is spaced from the fixed outer sheath by a plurality of annular membrane seals 280. This arrangement allows the inner cover 270 to float on the outer cover. As explained in connection with FIGS. 2 and 3, this is a slight misalignment, in particular any angle of fineness between the axis SS of the scanning arm 60 and the axis S'-S 'of the bore of the feedthrough 130. Allow 60 to be received without contacting the inner bearing surface of feedthrough 130.

The compliant vacuum feedthrough 130 provides an air bearing between the scanning arm 60 and the inner surface of the inner shroud 270, and also the atmospheric side of the feedthrough (left side in FIG. 4) and the vacuum side of the feedthrough ( A vacuum seal is provided between the right side of FIG. 4.

The air bearing portion of the vacuum feedthrough 130 is generally designated 290 and is provided with a series of through holes 300 formed radially through the inner cover 270. The inner cover 270 is formed of an outer cylinder 310 and an inner cylinder 320, which is an interference fit inside the outer cylinder 310. The inner cylinder 320 is formed of a porous material such as graphite. The through holes 300 penetrate the outer cylinder 310 wall and enter the inner cylinder 320 wall without penetrating therein. The plenum, which is closed at one end and open to the connection 340 at the other end, extends axially through the wall of the outer cylinder 310. The supply of compressed air is attached to the connection 340.

For ease of manufacture, the through holes 300 are mechanically manufactured to penetrate the outer cylinder 310 wall of the inner sheath 270 (before the inner sheath 270 is spaced apart from the outer sheath 260). Subsequently, the radially outer portions of the through holes 300 of the plenum 330 are blanked with grub screws or the like.

The inner diameters of the scanning arm 60 and the inner cover 270 of the inner cylinder 320 are each cylindrical, and since the air bearing 290 is disposed around the circumference in the inner cover 270, the plenum 330 Compressed air supply causes the scanning arm 60 to be centered relative to the inner diameter of the inner cylinder 320.

Atmospheric pressure vents 355 disposed around the circumference allow high pressure gas between the bearing surface of the scanning arm 60 and the inner cylinder 320 to escape to the atmosphere. The first vent is located in the axial middle portion of the length of the air bearing 290, and the second vent is located near the innermost end of the air bearing 290. This prevents pressure above atmospheric pressure from occurring in the vacuum feedthrough on the vacuum side of the air bearing 290.

The second portion of the vacuum feedthrough 130 is a differential-pumped vacuum seal, generally designated 360. It comprises a series of pumping rings 370A, 370B with pumping holes arranged radially. As shown, the membrane seals 280 are axially spaced between the inner and outer lids. Regions 285a and 285b between adjacent membrane seals 280 form compliant vacuum chambers. Pumping rings 370A, 370B are connected to these plenum chambers. Pumping devices (such as compliant vacuum hoses and rotary pumps; not shown) are attached to the outer cover which is fixed to the atmospheric pressure side of the feedthrough and are fixed to the atmospheric pressure side of the feedthrough in the feedthrough to the inner cover. Although only two pumping rings 370A, 370B are shown in FIG. 4, more pumping rings may be desirable depending on the efficiency of the sealing device, in particular the efficiency of the vacuum pumps attached to the vacuum pipes (and thus attached to the pumping rings). It will be appreciated. Other factors such as flight height (ie, the space between the outer bearing surface of the scanning arm 60 and the inner surface of the inner cylinder 320) will affect the number of differential steps in the differential-pumped vacuum seal.

The principles of differential-pumped vacuum seals are discussed in USSN 09 / 527,029, referenced above.

As shown in FIG. 4, the right side of the feedthrough 130 is at a reduced pressure in the vacuum chamber 40. The left side is the atmosphere. This is no different from the outer cover 260 fixedly mounted to the sledge 70. However, the inner sheath 270 floats inside the outer sheath 260 and to prevent shear of the membrane seals 280 from shearing due to significant forces (from left to right in FIG. 4) due to pressure differentials. Its inner cover 270 needs to be axially supported.

A thrust bearing assembly 390 is provided at the vacuum side end of the feedthrough 130 to provide the axial support while at least radially enabling compliance of the inner lid 270. The thrust bearing assembly 390 includes an annular reaction washer 400 which is screwed, riveted, or otherwise fixedly attached to the outer cover 260 and is not movable. A pair of trust washers 410, 420 are provided to the reaction washer 400 therein in the axial direction. The first thrust washer 410 is supported by a collar at the vacuum side end of the inner sheath 270.

The first trust washer 410 has a pair of radially opposite trust buttons 430b (only one of which is shown in FIG. 4) created on the first trust washer face. In general, the trust buttons 430b of the first trust washer bear the opposite surface of the second trust washer. Thus, the first thrust washer 410 can move in the X-Y plane about the axis provided by the two thrust buttons 430b facing in the radial direction.

The second thrust washer 420 has a pair of radially opposite thrust buttons 430a that bear the reaction washer 400 surface. The trust buttons 430a are disposed perpendicular to the trust buttons 430b of the first trust washer 410, thus allowing the second trust washers to move in the vertical X-Z plane.

Inner cover 270 by placing radially opposite trust buttons 430b on first trust washer 420 perpendicular to radially opposite trust buttons 430a on second trust washer 420. While the gimbal is gimbaled against the reaction washer 400 of the thrust bearing assembly 390, the thrust bearing assembly 390 provides a reaction against forces by atmospheric pressure. When the pressure in the vacuum chamber is reduced, forces act against each other and against the reaction washer 400 against the first and second thrust washers so that the washers are held in place in the axial direction without the need for additional fastening devices.

As an alternative to, or in addition to, the thrust bearing assembly 390, the inner shroud 270 is, for example, between the atmospheric end of the inner shroud 270 of the vacuum feedthrough and the fixed mounting point on the sledge 70. By means of a piano wire attached to it, it can be supported against axial forces from atmospheric pressure. While the device is simpler than gimbaled thrust bearing assembly 390, it is potentially not robust.

In FIG. 5, a perspective view of the substrate support 180 and the end of the scanning arm 60 attached thereto is shown. The substrate support 180 includes a chuck electrostatically holding a 300 nm diameter semiconductor wafer or the like. The chuck 440 electrostatically holds the semiconductor wafer in a manner known in the art. A first Faraday 450 is mounted adjacent to the chuck 440, details of which will be described below with respect to FIG. 9. The first Faraday 450 is generally parallel and coplanar to the surface of the chuck 440 on which the wafer is mounted. Faraday holes 460 are formed in the front surface 455 of the first Faraday 450. Typically, the holes have an area of about 1 cm 2.

The first Faraday 450 performs beam profiling prior to implantation into the wafer, i.e., the flow density with respect to the vertical plane of the incident ion beam in the X and Y directions (two orthogonal coordinate directions perpendicular to the ion beam direction). It is used to measure. In order to prevent wafer charging damage during implantation, and because the lateral position of the beam defines wafer angle alignment, this information is desirable to ensure a precise implant dose for the wafer to be implanted.

As described above, during implantation the ion beam is held in a fixed direction. However, the direction and dimensions of the ion beam may be "tuned" prior to implantation, for example by adjusting the physical and electrical parameters of the ion source that produces the ion beam. In order to measure the flow density of the ion beam prior to implantation using the apparatus of FIG. 5, the following procedure is followed. First, a dummy wafer is mounted to chuck 440. This is typically done by extending the scanning arm 60 vertically along the sledge 70 (FIGS. 1-3) to the reciprocating range in the y-direction. By driving the rotary motor of the scanning arm 60, the scanning arm 60 is rotated about its own axis in the P direction shown in FIG. 5 until it is horizontal, so that the chuck 440 plane rotates from vertical to horizontal. do. The dummy wafer is loaded into a load lock by a robot arm, which can be discharged to the atmosphere without having to evacuate the vacuum chamber 40.

When the dummy wafer is loaded, the substrate support 180 is rotated in reverse so that the chuck 440 is in a vertical position (XY plane), and then the fixed direction ion beam is flush with the hole 460 of Faraday. The scanning arm support structure 30 is moved in the y-direction along the sledge 70. Then, in order to profile the beam, linear motors 90A and 90B are driven such that Faraday 450 and substrate support 180 are moved together in the X direction.

In practice, the ion flow density decreases gently (ie not vertically) at the edge of the ion beam. Since the actual wafer is typically scanned across the beam in a raster fashion, it is particularly important to know the profile of the beam in the y-direction. In other words, the scanning arm support structure 30 is in a fixed position relative to the sledge 70 while the scanning arm 60 reciprocates from left to right until the entire substrate support crosses the ion beam in the x-direction. Remains. Then, the scanning arm support structure 30 is moved vertically, i.e. in the y-direction, by a distance related to the beam height, and then the scanning arm support structure 30 is once again in the sledge 70. The scanning arm 60 is again moved from right to left while being held in the stopped position. By repeating this process, the entire wafer can be implanted. To ensure that high and low ion density stripes do not occur in the y-direction, it is important to measure the beam profile before implantation. Profile measurements are supplied to a processor that controls the step size in the y-direction such that the overall implant density of ions remains relatively constant in the y-direction relative to the wafer.

Thus, by moving the scanning arm support structure 30 with respect to the sledge 70 such that the hole 460 of the Faraday 450 moves across the ion beam in the y-direction, the Faraday 450 is formed before the injection, The dummy wafer is scanned across the ion beam while in place. The charge collected by Faraday is measured as a function of distance (or time) from which the profile of the ion beam in the y-direction can be determined and used to set parameters for scanning of the wafer to be implanted.

Once the y-direction profile is obtained, linear motors 90A that hold the scanning arm support structure 30 in a fixed position relative to the sledge 70 and move the aperture 460 of Faraday 450 across the ion beam, X-profile can be obtained by extending scanning arm 60 using 90B). This is shown in FIG. 6. It will be noted that typically the area of the ion beam is wider than the area of the hole 460; For low ion implantation energy (1-5 kev), the ion beam has a relatively large area that decreases with increasing ion energy.

While the ion beam profile in the y-direction is particularly used to ensure accurate injection amount during implantation, the x- and y-direction profiles are useful for beam tuning before implantation. If the measured profiles in the x- and y-directions are considered not optimized by the operator (or a properly programmed processor), the beam line can be adjusted and the profiles can be remeasured prior to injection by the technique described above. have.

As an alternative to the process described above (which requires the mounting and remounting of the dummy wafer), a dual Faraday apparatus may be employed instead, with reference now to FIG. 7, which shows a cross-sectional view along line BB of FIG. 5. Will be explained. The device of FIG. 7 has a first Faraday 450 and a second Faraday 470 mounted radially opposite to the first Faraday 450 on the scanning arm 60 for use as described above. Adopts all. The second Faraday 470 includes its own hole 480. The second Faraday 470 and the holes 480 face away from each other when the chuck 440 is directed toward the ion beam as shown in FIG. 5. However, when the scanning arm 60 is rotated 180 ° about its own axis P (FIG. 5), the second Faraday is directed towards the incident ion beam as shown in FIG. 7 and the chuck 440 is directed to the first para. Headed opposite with day 450.

The substrate support 180 has a body 490, at least the back side of which may be coated with a semiconductor material forming a semiconductor layer. The portion of the scanning arm 60 adjacent the substrate support 180 is likewise preferably coated with a semiconductor material. Other suitable materials, such as graphite, which do not sputter or sputter material that will not damage the beam line, may be used to form a layer on the substrate support and / or the scanning arm. In such an apparatus, dummy wafers are unnecessary because layer 500 provides this function instead. Thus, beam profiling may be performed using the second Faraday 470 in exactly the same manner as described above with respect to the first Faraday 450.

In order to maintain the advantage of mounting Faraday or Faraday on the substrate support, the distance between the charge collector in the second Faraday and the longitudinal axis of the scanning arm 60 is equal to the charge in the first Faraday 450. It is preferred that the distance be equal to the distance between the point where it is collected and its longitudinal axis. If this geometry is maintained, when the substrate support 180 is rotated so that the chuck 440 is directed back towards the ion beam, the charge collector in the second Faraday 470 is on the same plane as the plane on which the wafer to be implanted is placed. Will be placed.

Although two separate Faradays 450, 470 are shown in FIG. 7, it is understood that a single physical structure incorporating the common (or adjacent) dividing member with the holes on the opposing face may be equally employed. Will be.

In fact, the possibility of cross-contamination (ie sputtering of previous beam species for subsequent wafers) means that the backside of substrate support 180 adopts a single Faraday, ie only a second Faraday in FIG. It may be desirable to have only 470 such that the hole of the single Faraday is obscured from the beam during injection.

If a Faraday facing the front side of the substrate support 180 (eg, Faraday 470 in FIG. 7) is employed, the front side of the substrate support will face the opposite side when the Faraday is facing the beam. . The front surface may then be coated with a contaminant material resulting from back-sputtering of ions from the beam stop downstream of the substrate support. In order to prevent this, it is preferable to include a protection portion that can fall against the front portion of the substrate support. The guard can be mounted on the scanning arm 60 or can be spaced apart from the chamber wall, for example.

8 shows an alternative arrangement for substrate support or scanning arm Faraday. 8 is a view along the beam line. Here, the Faraday 490 is mounted at a 90 ° angle to the chuck 440 plane and the rear surface of the substrate support. In this case, when the hole 460 is directed toward the ion beam, the chuck 440 is directed upward and thus away from the beam and any back sputtered material. Although a 90 ° angle between the plane of the Faraday hole and the chuck plane is desired, other angles such as about 120 ° (such that the chuck 440 is slightly opposite from the incident ion beam) can be employed.

A cross-sectional view of a preferred embodiment of Faraday 450 is shown in FIG. 9. Faraday includes a magnetic stainless steel housing 510 that is three-sided sealed and has a hole 460 in the front portion 455. The edges of the front portion 455 defining the holes 460 are formed with knife edges 520 for the purpose of the description below.

Within the housing 510 an electrometer 530 is connected to an outer stainless steel screen 540 and an inner graphite cup 550. A pair of permanent magnets 560 is positioned between the inner walls of the housing 510 and the outer walls of the graphite cup 550.

In particular, the purpose of the rotating plate 50 shown in FIGS. 1A and 1B is to allow the y-direction scanning to be performed in a plane other than vertical. The knife edge 520 of Faraday 450 shown in FIG. 9 accommodates a high implant angle. It is particularly preferred that the ion beam profile be measured with chuck and Faraday at subsequent implant angles.

It will be appreciated that the apparatus of FIG. 9 described in connection with the first Faraday 450 is equally applicable to the second Faraday 470 (FIG. 7). In particular, the knife edge 520 is still preferred if beam profiling is performed when the backside of the substrate support 180 faces toward the ion beam as shown in FIG. 7.

In addition, the use of Faraday mounted on the scanning arm 60 and / or adjacent to the substrate support is such that the holes of the Faraday (s) (or one of them) face forward (ie in the same direction as the chuck). Although described in terms of beam profiling prior to implantation, the Faraday may also be used for beam profiling during implantation. More specifically, if the Faraday is mounted close to the wafer on the chuck such that the Faraday hole is likewise close to the edge of the wafer and is directed towards the incident beam during implantation, then both the wafer and Faraday will at least match the Faraday hole. It is possible to arrange to pass in front of the beam with respect to part of the (y-direction). Thus, a complete beam profile can be obtained at least once per full wafer scan (all scanned x and y positions). In practice, by mounting two or more fares, each facing forward and spaced in the y-direction, one or more beam profiles per entire wafer scan can be obtained.

While various specific embodiments have been described, it will be understood that the embodiments are illustrative only and that various modifications may be made without departing from the scope of the invention as determined by the appended claims. It will also be understood that various features of the invention may be used together or separately.

Claims (50)

A semiconductor processing apparatus, wherein the apparatus A vacuum chamber having a chamber wall defining an aperture therein; An elongate member extending through said aperture of said chamber wall and movable longitudinally through said chamber wall; An elongate member driver arranged to reciprocate said elongate member in said longitudinal direction; A carrier external to said vacuum chamber for supporting said elongate member and said elongate member driver; And And a carrier driver arranged to reciprocate the carrier in a direction generally perpendicular to the reciprocating direction of the movable elongate member. The semiconductor processing apparatus according to claim 1, wherein the elongate member driver is a linear motor to which the elongate member is attached. The semiconductor processing apparatus according to claim 1 or 2, wherein the carrier driver is a linear motor. 4. The semiconductor processing apparatus of claim 1, wherein the movable elongate member is mounted on a slide that is cantilevered from the carrier. 5. The semiconductor processing apparatus of claim 4, wherein the apparatus further comprises a linear motor arranged to drive the elongate member relative to the slide. 6. The chamber of claim 1, wherein the chamber wall defines an aperture, the carrier serves as a movable lid for the aperture, and the elongate member is through the carrier and the chamber wall. Extending through said hole in the semiconductor processing apparatus. 7. The semiconductor of claim 6, wherein the carrier comprises a feedthrough for the elongate member, wherein the elongate member and the feedthrough together define a vacuum-tight seal. Process equipment. 8. The semiconductor processing apparatus of claim 7, wherein the feedthrough includes a compliant closed structure, wherein the elongate member is supported relative to the carrier by at least one bearing spaced apart from the feedthrough in turn. The semiconductor processing apparatus of claim 8, wherein the compliant hermetic structure comprises a fluid bearing. 10. The semiconductor processing apparatus of claim 1, wherein the apparatus further comprises a force compensator arranged to counteract a fixed force acting on the movable elongate member. 11. 10. The apparatus of any one of claims 6-9, wherein the device further comprises a vacuum-tight fluid bearing disposed between the chamber wall and the carrier, the fluid bearing being adjacent to the bore. The semiconductor processing apparatus. 12. The semiconductor processing apparatus of claim 1, wherein the elongate member is further rotatable about an axis parallel to the longitudinal direction. The semiconductor processing apparatus according to claim 1, wherein the carrier is further rotatable about an axis parallel to the longitudinal direction. 14. The apparatus of claim 13, further comprising a base supported by the chamber wall and an annular rotor rotatably mounted on the base and having first and second surfaces generally planar, And the carrier is mounted on one of the generally planar faces of the annular rotor and disposed to reciprocate across the one of the generally planar faces of the annular rotor. As a semiconductor processing apparatus, The device is A vacuum chamber having a chamber wall; An elongate member extending horizontally through said chamber wall and movable longitudinally through said chamber wall; An elongate member driver disposed to drive the elongate member in the longitudinal direction; A carrier for supporting the elongate member and driver that is external to the vacuum chamber and provides cantilever support for an outer end of the elongate member; And And a feedthrough into the vacuum chamber for receiving the elongate member and including a vacuum seal for sealing against the elongate member. 16. The semiconductor processing apparatus of claim 15, wherein the vacuum seal is compliant. 17. The apparatus of claim 15 or 16, wherein the carrier comprises a slide, the elongate member is disposed along the slide, and the semiconductor processing apparatus further comprises a fluid bearing between the elongate member and the slide. Semiconductor processing equipment. 18. The elongated member of claim 17, wherein the fluid bearing comprises a support member disposed to support the elongate member with respect to the slide, and a gimbal head defining a first fluid bearing surface. A semiconductor processing apparatus forming a second fluid bearing surface. 19. The semiconductor processing apparatus of claim 18, wherein the support member of the fluid bearing is compliant in a direction generally perpendicular to the first and second fluid bearing surfaces. 20. The semiconductor processing apparatus according to any one of claims 15 to 19, wherein the elongate member driver comprises at least one linear motor. 21. The semiconductor processing apparatus of claim 20, wherein the elongate member is inserted between two linear motors. 22. The apparatus of claim 21, wherein the carrier comprises a slide having a fixed position relative to the carrier, the semiconductor processing apparatus comprising: a first bearing disposed between the slide and the first linear motor, and the slide and the three And a second bearing between the elongate members. 23. The apparatus of claim 22 wherein the first bearing comprises a plurality of fluid bearing members arranged to support the elongate member toward the end of the elongate member, wherein each fluid bearing is in the longitudinal direction of the elongate member. And a gimbaled head defining a first fluid bearing surface and a support member that is compliant in a direction generally perpendicular to the axis, wherein the slide provides a second fluid bearing surface for each fluid bearing member. . 24. The feedthrough of any one of claims 15 to 23 wherein the feedthrough is compliant in a direction perpendicular to the longitudinal axis of the elongate member, wherein the vacuum seal is a differentially pumped vacuum seal. Semiconductor processing equipment. 25. The rotation drive means according to any one of claims 15 to 24, wherein the elongate member is circular in cross section, and the semiconductor processing apparatus is arranged to selectively rotate the elongate member about its longitudinal axis. Further comprising a semiconductor processing apparatus. 27. The semiconductor processing apparatus of any one of claims 15 to 26, wherein the semiconductor processing apparatus further comprises a force compensator arranged to cancel a fixed force acting on the movable elongate member. A method of mounting an elongate member for reciprocating into and out of a vacuum chamber of a semiconductor processing apparatus, the method comprising: (a) the elongate member, supported by at least one load bearing device positioned towards the first end of the elongate member, external to the vacuum chamber; Supporting against; And (b) mounting the elongate member to penetrate a vacuum seal between the interior and exterior of the vacuum chamber, The rod provided by the elongate member is substantially supported by the rod bearing devices or each thereof so that the vacuum seal serves as a non-load bearing guide for the elongate member during reciprocating movement. Elongate member wearing method to do. 28. The device of claim 27, wherein the rod bearing devices or each of them has an adjustable length, includes a support that is compliant in the length adjusting direction, and a gimbaled head, Supporting the elongate member includes: Adjusting the rod bearing devices or their respective lengths until the gimbaled head is in contact with the carrier; And Providing an fluid supply to the area of the gimbaled head to form a fluid bearing between the gimbaled head and the carrier by lifting the gimbaled head away from the carrier. Way. A vacuum seal for a feedthrough of an elongate member extending into a vacuum chamber of a semiconductor processing apparatus, the vacuum chamber having a chamber wall member, wherein the vacuum seal is: An outer mounting portion fixed to the wall member and having a longitudinal axis extending in a direction passing through the chamber wall member; It is radially mounted inwardly in the outer mounting portion, movable relative to the outer mounting portion, the elongate member is sized to be accommodated therethrough and extends in the direction of passing through the chamber wall as well. An internal bearing having an axis; And And a plurality of resilient gaskets disposed between the inner bearing and the outer mount and spaced apart axially along the longitudinal axis of the inner bearing and the outer mount. 30. The vacuum seal of claim 29, wherein the vacuum seal further comprises a counter balance arranged to provide a reaction to axial forces acting on the inner bearing. 31. The vacuum seal of claim 30, wherein the balance comprises a reaction plate fixed relative to the external mount. 32. The vacuum seal of claim 31, wherein the equilibrium further comprises a gimbaled thrust plate device that exerts a force on the reaction plate. 33. The apparatus of claim 32, wherein the gimbaled trust plate device comprises first and second trust plates, each trust plate including two trust buttons facing in the radial direction, and a trust button on the first trust plate. Are vertically offset from the trust buttons on the second trust plate, the trust buttons of the first trust plate exerting a force toward the second trust plate in use and in turn the trust buttons of the second trust plate. And a force acting against the reaction plate during use. 31. The vacuum seal of claim 30, wherein the balance comprises a high tensile strength wire secured to the inner bearing. 35. The method of any one of claims 29 to 34, wherein the inner bearing provides a first rotating bearing surface, the elongate member provides a second rotating bearing surface, and the first and second rotating bearing surfaces. And a fluid supply is provided to said vacuum seal to form a fluid bearing between them. 36. The apparatus of claim 35, wherein the vacuum seal is configured to maintain a pressure difference between a first portion of the elongate member on the atmospheric pressure side of the vacuum seal and a second portion of the elongate member inside the vacuum chamber. And a differential pumped groove in the inner bearing. In a semiconductor processing apparatus, the apparatus is: A vacuum chamber having a chamber wall with holes; Opposing an elongate arm extending through the aperture of the chamber wall, and a front portion adapted to receive a substrate to be processed and attached to the first end of the elongate arm and within the vacuum chamber; A substrate scanning device including a substrate support including a rear surface; Scanning device driving means for moving said substrate scanning device in a first direction generally penetrating said chamber wall in a longitudinal direction and in a second direction generally perpendicular to said first direction; And And a Faraday mounted adjacent to the substrate support in a fixed relationship with the substrate support. 38. The apparatus of claim 37, wherein the semiconductor processing apparatus is: About an axis parallel to the first direction of elongate arm movement between a first position where the front surface portion of the substrate support faces toward the incident ion beam and a second position where the rear surface portion of the substrate support faces toward the incident ion beam And a rotation drive means for rotating the substrate support. 39. The apparatus of claim 38, wherein the Faraday is mounted adjacent to the front portion of the substrate support and the semiconductor processing apparatus further comprises: the substrate support for beam profiling when the substrate support is rotated to the second position. And a second Faraday mounted in a fixed relationship with the substrate support adjacent to the back side. 40. The substrate of claim 38 or 39, wherein the Faraday has front and rear openings, the front opening is disposed adjacent the front portions of the substrate support, and the back opening is adjacent the rear portion of the substrate support. And a semiconductor processing apparatus. 41. The semiconductor processing apparatus according to any one of claims 38 to 40, wherein the backside portion of the substrate support is formed of or coated with a material selected from a list comprising a semiconductor material and graphite. 42. The semiconductor processing apparatus of claim 38, wherein the elongate arm is coated with a material selected from the list comprising semiconductor material and graphite. A method of profiling an ion beam in a semiconductor processing apparatus, said apparatus comprising a vacuum chamber having a chamber wall with holes, an elongate arm extending through said hole in said chamber wall and a first end of said elongate arm A beam scanning device comprising a substrate support attached to and positioned within the vacuum chamber, the substrate support comprising a front portion adapted to receive a substrate to be processed, and a back portion opposite the front portion, The ion beam profiling method is: Mounting a Faraday in a fixed relationship with the substrate support adjacent to the substrate support; In either direction, the first direction generally penetrating the chamber wall in a longitudinal direction and the second direction generally perpendicular to the first direction, the ion beam is generally aligned with the first or second direction in the Faraday, respectively. Moving the beam scanning apparatus until it is completed; Scanning the beam scanning device in a direction of the other of the first and second directions such that the ion beam passes across the faraday; Obtaining a Faraday output signal while the beam scanning device is scanning across the Faraday; And And obtaining a profile of an ion beam in the other of the first and second directions from the Faraday output signal. 44. The method of claim 43, wherein the method further comprises mounting a dummy substrate on the substrate support prior to moving the substrate scanning device. 45. The substrate of claim 43 or 44, wherein the Faraday has a Faraday aperture in its face, the Faraday aperture faces away from the front portion of the substrate support and towards the rear side of the substrate support. And the ion beam profiling method further comprises rotating the substrate support about an axis parallel to the first direction until the Faraday aperture is towards the ion beam. 46. The method of any one of claims 43 to 45, wherein the beam scanning device further comprises a second Faraday mounted adjacent to the back portion of the substrate support, wherein the ion beam profiling method comprises: Rotating the substrate support about an axis parallel to the first direction until a back side is closer to the source of the ion beam than the front side; The beam scanning apparatus is moved in the one of the first and second directions until the ion beam is aligned with the second Faraday, and crosses the first and second Faraday. In the direction of the other one of the And the profile of the ion beam is obtained from the output of the second Faraday. 47. The method of any of claims 43-46, wherein the ion beam profiling method further comprises a shield to cover the front portion of the substrate support prior to performing the step of moving the beam scanning device. , Ion beam profiling method. 48. The apparatus of any one of claims 43 to 47, wherein the Faraday has opposing first and second sides with apertures, respectively, wherein the first side is adjacent to the front portion of the substrate support. The Faraday is mounted such that a second side is adjacent to the rear portion of the substrate support; The ion beam profiling method prior to moving the beam scanning device: Rotating the substrate support about an axis parallel to the first direction until the rear portion of the substrate support is closer to the source of the ion beam than the front portion; And the ion beam is aligned with the second side of the Faraday during scanning to obtain the ion beam profile. As an ion implanter, 43. The ion implanter comprises an ion beam generator for generating a beam of ions to be implanted into a substrate mounted inside a semiconductor processing apparatus according to any one of claims 1 to 29 or 40 to 42. Injector. A semiconductor processing apparatus, the apparatus comprising: A vacuum chamber having a chamber wall defining a chamber wall hole; A base supported by the chamber wall; An annular rotor rotatably mounted on said base and defining a rotor aperture coincident with said chamber wall aperture and having generally planar first and second faces; An elongate member extending through the rotor and chamber wall holes and movable longitudinally through the rotor and chamber wall; An elongate member driver arranged to reciprocate in the longitudinal direction; A carrier mounted adjacent the first outer surface of the rotor to support the elongate member and driver; And And a carrier driver arranged to reciprocate in a direction generally perpendicular to the reciprocating direction of the movable elongate member.